improve python dringctl tool
Issue generated from Tuleap's migration script. Originally submitted by: Patrick Keroulas (pkeroulas)
- Support python2.7 in addition to python3 (super() function is impacted)
- make import robust (Gobject binding and ConfigParser)
- Update dbus call interface (callStateChanged signal for instance)
- add "auto answer" option
- add interrupt signal handler to exit glib.mainloop()